Bars comprising relatively small amounts of surfactant (e.g., less than about 25% by wt.) and high amounts of sugar (greater than about 40% by wt.) have been disclosed, for example, in applicants' co-pending application entitled “Skin Cleansing Bar Comprising High Levels of Saccharides”, U.S. Ser. No. 10/682,698 to Patel et al., filed Oct. 9, 2003, hereby incorporated by reference into the subject application ('698). Compositions of the '698 application also comprises 5 to 20% by wt. glass transition modifier and 1 to 30% by wt. water.
While the compositions of '698 comprise large amounts of sugar, the level of soap (e.g., fatty acid soap) is never required to be at least 20%, preferably at least 30% of the composition, nor is there an appreciation that special processing steps must be conducted to ensure that such high levels of soap and sugar can be extruded.
Unexpectedly, applicants have found that, by requiring floor level amounts of soap (i.e., at least 20%, preferably at least 30% by wt. of soap) and by ensuring certain process criticalities are met, it is possible to produce the bar compositions through an extrusion route (e.g., after mixing, optionally milling, cooling and optionally stamping) rather then, as previous believed, only producing such bars through a melt cast route. Bars made following both the composition and process criticalities of the invention will have optimal yield stress (e.g., 90 to 300 kilopascals (kPa), wherein yield stress is measured by equation 122.6/length of cut (in centimeters) made in a bar cut by cheesewire, as defined in protocol section) such that they can be readily extrudable, high sugar bars.
In a second embodiment of the invention, the invention comprises a process for making a low surfactant, high sugar bar (the less surfactant and the more sugar used provides good economic advantage in bar manufacture) via an extrusion route which process comprises mixing at least 20%, preferably at least 25%, more preferably at least 30% soap with sufficient water (i.e., 15-25% H2O) and at sufficient temperature (above about 50° C.) to ensure soap solubility; and only subsequently mixing in sugars (optimally adding those with more reducing groups subsequent to those with fewer or none). Co-structurants can be added either with the soap and water, or with the sugar(s). Water levels are adjusted to ensure optimal yield stress after all ingredients are mixed and prior to milling (optional step), chilling and extrusion.
The '698 application noted above contemplates production only by melt cast route. Other art of which applicants are aware also either does not contemplate production of high sugar bars by extrusion route or does not use high sugar and high fatty acid soap criticalities (let alone envisage the process criticalities required when both are used) as required in the subject invention.
U.S. Pat. No. 6,376,441 to Ross et al. discloses a multi-phase melt cast bar.
U.S. Pat. No. 6,475,979 discloses bar which may have 5-90% surfactant and 10-85% which can be carbohydrate structurant such as starch or maltodextrin. The invention contemplates use of a reduced maltosaccharide which does not discolor during processing. There is no disclosure, however, of the high sugar, high fatty acid requirements of the invention; no disclosure that soap synthetic be less than about 52%, preferably less than 50%, more preferably less than about 45% by wt. composition; and no disclosure of the processing requirements needed when extruding such compositions.
U.S. Pat. No. 5,756,438 discloses a cleansing bar containing 40% to 80% of filler such as dextrin/dextrose to reduce cost is to 45% non-soap detergent and 10 to 20% waxy binder. These are non-soap detergents.
U.S. Pat. No. 6,680,285 to Abbas et al. discloses skin cleansing bar with 15-60% by wt. surfactant and 5 to 20% emollient. Again, the high soap, low surfactant and the process criticalities of the present invention are not contemplated.
These and other aspects, features and advantages will become apparent to those of ordinary skill in the art from a reading of the following detailed description and the appended claims. For the avoidance of doubt, any feature of one aspect of the present invention may be utilized in any other aspect of the invention. It is noted that the examples given in the description below are intended to clarify the invention and are not intended to limit the invention to those examples per se. Other than in the experimental examples, or where otherwise indicated, all numbers expressing quantities of ingredients or reaction conditions used herein are to be understood as modified in all instances by the term “about”. Similarly, all percentages are weight/weight percentages of the total composition unless otherwise indicated. Numerical ranges expressed in the format “from x to y” are understood to include x and y. When for a specific feature multiple preferred ranges are described in the format “from x to y”, it is understood that all ranges combining the different endpoints are also contemplated. Where the term “comprising” is used in the specification or claims, it is not intended to exclude any terms, steps or features not specifically recited. All temperatures are in degrees Celsius (° C.) unless specified otherwise. All measurements are in Si units unless specified otherwise. All documents cited are—in relevant part—incorporated herein by reference.